论文标题
黑洞空位中的扩展体运动：有什么可能？
Extended-body motion in black hole spacetimes: What is possible?
论文作者
论文摘要
自由落体在一般相对论中仅是通用的。不同的扩展物体可能以不同的方式落下，具体取决于它们的内部动力。然而，他们的运动的某些方面是普遍的。本文探讨了D型Dype PaceTime中对体体运动的普遍限制。在四极近似值中工作，我们表明，除了通过杀死矢量施加的（以前的）约束外，重力扭矩的两个组成部分还必须消失。此外，在身体四极矩的十个成分中，发现四个是无关紧要的，两个可以仅影响力，其余四个可以影响力和扭矩。作为应用程序，我们考虑了假设的航天器的能力，该航天器通过控制其内部结构来控制其运动。在Schwarzschild时空中，这样的航天器可以控制其质量，并且这样做可以稳定不稳定的轨道，逃离绑定的轨道等等 - 所有这些都没有火箭。
Free-fall is only approximately universal in general relativity. Different extended bodies can fall in different ways, depending on their internal dynamics. Nevertheless, certain aspects of their motion are universal. This paper examines the universal constraints on extended-body motion in vacuum type D spacetimes. Working in the quadrupole approximation, we show that in addition to the (previously-known) constraints imposed by Killing vectors, two components of the gravitational torque must vanish. Furthermore, of the ten components of a body's quadrupole moment, four are found to be irrelevant, two can affect only the force, and the remaining four can affect both forces and torques. As an application, we consider the capabilities of a hypothetical spacecraft which controls its motion by controlling its internal structure. In the Schwarzschild spacetime, such a spacecraft can control its mass, and in doing so, it can stabilize unstable orbits, escape from bound orbits, and more -- all without a rocket.
